Aircraft employ a wide variety of doors which are exposed to the surrounding environment about the aircraft. Passenger ingress and egress doors and storage compartment doors permit access to the interior of the aircraft and are typically opened and closed while the aircraft is on the ground. In addition, there is a variety of flight actuated doors which are opened and closed during various times during aircraft flight. Common examples of flight actuated doors are weapons bay doors (in military aircraft), sensor suite doors, landing gear doors and auxiliary air doors.
Aircraft are subjected to various external and internal loads which may result in temporary deformations of the door frames which are located at various places about the aircraft. For example, it is typical for an aircraft to store fuel within its wings. Thus, when the aircraft is fueled the wings may tend to droop and the bottom side of the fuselage to be in a compressive state. When the aircraft is in flight, a variety of aerodynamic forces may act to upwardly push the wings and cause the bottom side of the fuselage to be in a relative tension state. Where there are doors located at regions of the aircraft which are locally subject to such forces (e.g., landing gear doors and weapons bay doors) the door frames thereof may deform, both in the plane of the door frame and out of the plane of the door frame.
Such deformations may result in the formation of gaps or discontinuities between the door and the door frame. As such, the reduction or mitigation of any gaps or discontinuities at or around the door frame is especially desirable because they tend to increase the radar signature of the aircraft.
In addition, it is often desirable that aircraft doors must be able to withstand pressure differentials between the interior and exterior of the door. Typically the interior pressure is greater than the external pressure (i.e., burst pressure). Such a pressure may be a function of the placement of the door upon the aircraft, altitude, and relative aircraft speed. A positive cabin pressure is typically maintained to provide for a hospitable environment. The door frame deformations, however, may result may result in poor or improper sealed engagement between the door and the door frame.
Though conventional aircraft doors are provided with seals about the perimeter of the door, such seals possess certain deficiencies which detract from their overall utility. In this respect, the prior art seals are typically designed to be highly flexible to allow for extreme deformations of the associated door frame. However, because of this high degree of flexibility, such seals are susceptible to poor sealing engagement with the door frame and are therefore inadequate to mitigate gaps and discontinuities when subjected to pressure differentials between the interior and exterior of the aircraft.
Accordingly, there is a need in the art for an aircraft door which is capable of substantially maintaining contact with a door frame which is susceptible to deformation in order to reduce or mitigate a perimeter gap occurring between the door and the door frame.